The Golden Age of Detective Fiction was an era of classic murder mystery novels, predominantly from the 1920s and 1930s. Well known writers of the Golden Age include Agatha Christie, Dorothy L Sayers, Margery Allingham, Ronald Knox, Anthony Berkeley and G. K. Chesterton.

But these books have roots in earlier works of detective fiction, and there are still mysteries being written today that would fit in with the ‘feel’ of the Golden Age (Anthony Horowitz is an excellent example of a modern day writer of contemporary ‘Golden Age’ mysteries).

There is a debate around which book can be called the first mystery story, but not many would argue that the first modern detective story is The Murders in the Rue Morgue by Edgar Allan Poe, first published in 1841. Other early examples of the mystery writers are:

• Wilkie Collins – The Woman in White (1859) and The Moonstone (1868)
• Charles Dickens – Bleak House (1853) and The Mystery of Edwin Drood (1870)
• Anna Katherine Green – The Leavenworth Case (1878)
• Fergus Hume – The Mystery of the Hansom Cab (1886)
• Arthur Conan Doyle – Sherlock Holmes first appeared in A Study in Scarlet (1887)
• Baroness Orczy – The Man in the Corner (1901) and Lady Molly of Scotland Yard (1910)
• E. C. Bentley – Trent’s Last Case (1913)

Although these writer’s (and all the other early mystery writers I have missed) would not generally be included in a list of writers of Golden Age Mysteries, they were influential in the development of the mystery genre, so I have made the decision that I will include any reviews I do of these older books with the writers who are more generally accepted as being Golden Age.

The Golden Age is also seen by many to be predominantly Western, with most of the best known authors being English. Most of the books I will be including here were written by members of the Detection Club, a group formed in London by Anthony Berkeley and Dorothy L Sayers in 1930. But there are equivalents of the Golden Age around the world, and many of these books are now being translated into English. I’ve recently discovered the Japanese equivalent (honkaku) with the works of Seishi Yokomizo and will be including his, and other Japanese honkaku writers’ books in this reading project.

The rules of Golden Age mysteries were codified in 1929 by Ronald Knox in his ‘Ten Commandments’. According to Knox, a detective story “must have as its main interest the unravelling of a mystery; a mystery whose elements are clearly presented to the reader at an early stage in the proceedings, and whose nature is such as to arouse curiosity, a curiosity which is gratified at the end.”

Knox's ‘Ten Commandments’ are:

1. The criminal must be mentioned in the early part of the story, but must not be anyone whose thoughts the reader has been allowed to know.
2. All supernatural or preternatural agencies are ruled out as a matter of course.
3. Not more than one secret room or passage is allowable.
4. No hitherto undiscovered poisons may be used, nor any appliance which will need a long scientific explanation at the end.
5. No Chinaman must figure in the story (this was a reaction to and criticism of racial cliches which were common in English writing in the 1920s.)
6. No accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right.
7. The detective himself must not commit the crime.
8. The detective is bound to declare any clues which he may discover.
9. The ‘sidekick’ of the detective, the Watson, must not conceal from the reader any thoughts which pass through his mind: his intelligence must be slightly, but very slightly, below that of the average reader.
10. Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.

S. S. Van Dine wrote a more detailed list of rules in the article “Twenty Rules for Writing Detective Stories” in 1928. These are known as Van Dine’s Commandments (listed at the end of my review for The Benson Murder case).